Tagging objects in indoor spaces using ambient, distributed backscatter

ABSTRACT

A product tagging system is provided. The product tagging system includes at least one RF backscatter transmitter configured to emit a Radio Frequency (RF) signal on a frequency. The product tagging system further includes a passive RF backscatter tag associated with a product and configured to reflect and frequency shift the RF signal to a different frequency. The product tagging system also includes at least one RF backscatter receiver configured to read the product on the different frequency by detecting a distributed ambient backscatter signal generated by a reflection and frequency shifting of the RF signal by the passive RF backscatter tag.

RELATED APPLICATION INFORMATION

This application claims priority to U.S. Provisional Application No.62/657,704, filed on Apr. 13, 2018, and U.S. Provisional Application No.62/696,928, filed on Jul. 12, 2019, incorporated herein by reference intheir entireties.

BACKGROUND Technical Field

The present invention relates to object detection and more particularlyto tagging objects in indoor spaces using ambient, distributedbackscatter.

Description of the Related Art

Today, retailers are unable to gather insights into the shopping andconsumption behavior of everyday products by their consumers. Thisarises from the inability to tag and monitor everyday products inconsumer spaces in a cost-effective and scalable manner. Hence, there isa need for a way to tag everyday products in consumer spaces in acost-effective and scalable manner.

SUMMARY

According to another aspect of the present invention, a product taggingsystem is provided. The product tagging system includes at least one RFbackscatter transmitter configured to emit a Radio Frequency (RF) signalon a frequency. The product tagging system further includes a passive RFbackscatter tag associated with a product and configured to reflect andfrequency shift the RF signal to a different frequency. The producttagging system also includes at least one RF backscatter receiverconfigured to read the product on the different frequency by detecting adistributed ambient backscatter signal generated by a reflection andfrequency shifting of the RF signal by the passive RF backscatter tag.

According to another aspect of the present invention, a method isprovided for product tagging. The method includes emitting, by at leastone RF backscatter transmitter, a Radio Frequency (RF) signal on afrequency. The method further includes reflecting and frequencyshifting, by a passive RF backscatter tag associated with a product, theRF signal to a different frequency. The method also includes reading, byat least one RF backscatter receiver, the product on the differentfrequency by detecting a distributed ambient backscatter signalgenerated by a reflection and frequency shifting of the RF signal by thepassive RF backscatter tag.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will provide details in the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a block diagram showing an exemplary processing system towhich the present invention may be applied, in accordance with anembodiment of the present invention;

FIG. 2 is a block diagram showing an exemplary RF backscatteringmechanism to which the present invention can be applied, in accordancewith an embodiment of the present invention;

FIG. 3 is a block diagram showing an exemplary operation of the presentinvention involving harmonic tags, in accordance with an embodiment ofthe present invention;

FIG. 4 is a block diagram showing an exemplary operation of the presentinvention involving frequency-shifting tags, in accordance with anembodiment of the present invention;

FIG. 5 is a block diagram showing an exemplary operation of the presentinvention involving a mono-static setup that uses a mobile device, inaccordance with an embodiment of the present invention;

FIG. 6 is a block diagram showing an exemplary operation of the presentinvention involving a mono-static setup that uses a static device, inaccordance with an embodiment of the present invention;

FIG. 7 is a flow diagram showing an exemplary method for tagging objectsin indoor spaces using ambient, distributed backscatter, in accordancewith an embodiment of the present invention;

FIG. 8 is a block diagram showing an exemplary store environment towhich the present invention can be applied, in accordance with anembodiment of the present invention;

FIGS. 9-10 are flow diagrams showing an exemplary method for maintainingan in-store inventory, in accordance with an embodiment of the presentinvention;

FIG. 11 is a block diagram showing an exemplary environment enabled withtagged navigation markers to which the present invention can be applied,in accordance with an embodiment of the present invention; and

FIGS. 12-13 are flow diagrams showing an exemplary method for indoornavigation assistance, in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to tagging objects in indoor spacesusing ambient, distributed backscatter.

In an embodiment, an ambient, distributed, orthogonal back scatteringsolution is provided. One or more embodiments of the present inventioninvolve low-cost, passive, orthogonal backscattering tags to tageveryday products, while repurposing the existing wireless interfaces insmart devices (e.g., smartphones, voice-activated speakers, and soforth) to monitor the products (read the tags). By leveraging ambientbackscattering, embodiments of the present invention do not require anRFID infrastructure, and by enabling orthogonal bands (one band fortransmitting and another band for receiving) through its carefullydesigned passive tags, can accomplish backscattering using two separate(existing) devices without the need for self-interference cancelation.The present invention can be used to show significant insights intoconsumer shopping behavior for retailers as well as provide otherbenefits as readily appreciated by one of ordinary skill in the artgiven the teachings of the present invention provided herein.

FIG. 1 is a block diagram showing an exemplary processing system 100 towhich the present invention may be applied, in accordance with anembodiment of the present invention. The processing system 100 includesa set of processing units (e.g., CPUs) 101, a set of GPUs 102, a set ofmemory devices 103, a set of communication devices 104, and set ofperipherals 105. The CPUs 101 can be single or multi-core CPUs. The GPUs102 can be single or multi-core GPUs. The one or more memory devices 103can include caches, RAMs, ROMs, and other memories (flash, optical,magnetic, etc.). The communication devices 104 can include wirelessand/or wired communication devices (e.g., network (e.g., WIFI, etc.)adapters, etc.). The peripherals 105 can include a display device, auser input device, a printer, an imaging device, and so forth. Elementsof processing system 100 are connected by one or more buses or networks(collectively denoted by the figure reference numeral 110).

In an embodiment, memory devices 103 can store specially programmedsoftware modules in order to transform the computer processor system ina special purpose computer configured to implement various aspects ofthe present invention. In an embodiment, special purpose hardware (e.g.,Application Specific Integrated Circuits, and so forth) can be used toimplement various aspects of the present invention.

Of course, the processing system 100 may also include other elements(not shown), as readily contemplated by one of skill in the art, as wellas omit certain elements. For example, various other input devicesand/or output devices can be included in processing system 100,depending upon the particular implementation of the same, as readilyunderstood by one of ordinary skill in the art. For example, varioustypes of wireless and/or wired input and/or output devices can be used.Moreover, additional processors, controllers, memories, and so forth, invarious configurations can also be utilized as readily appreciated byone of ordinary skill in the art. These and other variations of theprocessing system 100 are readily contemplated by one of ordinary skillin the art given the teachings of the present invention provided herein.

Moreover, it is to be appreciated that various figures as describedbelow with respect to various elements and steps relating to the presentinvention that may be implemented, in whole or in part, by one or moreof the elements of system 100. Moreover, system 100 can be used toanalyze results of the tagging and to perform actions responsive totagging results. These and other uses of system 100 are readilydetermined by one of ordinary skill in the art given the teachings ofthe present invention provided herein, while maintaining the spirit ofthe present invention.

One or more embodiments of the present invention leverage passive radiofrequency (RF) tags to tag and monitor everyday objects. Passive RF tagsdo not require a battery and cost a few cents each. The RF tags can bepasted onto objects and work by simply backscattering (reflecting) thesignal energy sent by the transmitter, thereby eliminating the need togenerate their own signal, as shown in FIG. 2. By modulating the stateof the reflected signal, the tag is able to convey information stored init, which could be related to the object that it tags. While the amountof information that can be delivered by a RF tag is limited (few tens tohundreds of Kbps for UHF tags), its low cost, small form factor andpassive nature, allows for scalable tagging of everyday objects inconsumer spaces.

FIG. 2 is a block diagram showing an exemplary RF backscatteringmechanism 200 to which the present invention can be applied, inaccordance with an embodiment of the present invention.

The backscattering mechanism 200 involves a passive RF tag 210 and an RFreader 220 with an RF antenna 221.

In FIG. 2, d denotes a distance between the RF antenna 221 to the RF tag210, λ denotes a wavelength of the transmitted wave 230, θ_(T) denotesthe phase of the transmit signal, θ_(R) denotes the phase of thebackscattered received signal, and f₁ denotes a frequency of thetransmitted wave 230 and also of the backscatter wave 240.

In operation, a Radio Frequency (RF) wave 230 is transmitted from theantenna 221 of the RF reader 220. Depending upon an orientation of theRF tag 210, the RF wave 230 reflects the RF wave 230 back to the RFantenna 221 as a backscatter wave 240. Moreover, by modulating the stateof the reflected signal, i.e., the backscatter wave 240, the passive RFtag 210 is able to convey information stored in the passive RF tag 210.

The present invention enables low-cost, reliable tagging of everydayobjects through the innovation of ambient, distributed, orthogonal-bandbackscattering on existing WIFI and Bluetooth capable devices. It hasthe following features. A first feature is (i) ambient: it leveragesexisting RF technologies such as WIFI and Bluetooth in smart devices,hubs and routers, that are already present in indoor spaces to enablebackscattering. This avoids the need for an additional RFID-specificinfrastructure (RFID readers and antennas). A second feature is (ii)distributed: instead of relying on a single, mono-static backscatterreader (i.e., joint Tx and Rx) with limited read reliability, itdistributes the Tx and Rx functionality (henceforth referred to as B-Txand B-Rx) of backscattering to two distributed devices in theenvironment (bi-static backscattering); this allows for the mobility ofone or both of these devices to increase the diversity of channels andhence the reliability of tag reads. A third feature is (iii) orthogonalbackscattering: bi-static readers deployed on two different devices (notjust antennas), but same frequency band, face a serious issue known asself-interference; the latter significantly degrades the receiver'sability to decode the tag responses. The present invention eliminatesthis issue by instrumenting an orthogonal-band tag. The latter iscapable of either backscattering simultaneously on an additional bandthat is orthogonal to that used by the B-Tx (dual-band tags), orbackscattering directly on a different orthogonal channel(frequency-shifting tags). Both these approaches allow the B-Rx tobypass the need for canceling self-interference by receiving the tag'sresponse on a band that is different (orthogonal) from that of the B-Tx.

A description will now be given regarding ambient, distributedbackscatter, in accordance with one or more embodiments of the presentinvention.

The present invention operates as shown in FIGS. 3-6. FIG. 3 is a blockdiagram showing an exemplary operation 300 of the present inventioninvolving harmonic tags, in accordance with an embodiment of the presentinvention. In FIG. 3, a fixed frequency differential is used such thatΔf=k·f₁. The exemplary operation 300 is between a tag 310, a device 320hosting B-Tx, and a device 330 hosting B-Rx. FIG. 4 is a block diagramshowing an exemplary operation 400 of the present invention involvingfrequency-shifting tags, in accordance with an embodiment of the presentinvention. In FIG. 4, a flexible Δf is used. The exemplary operation 400is between a tag 410, a device 420 hosting B-Tx, and a device 430hosting B-Rx. FIG. 5 is a block diagram showing an exemplary operation500 of the present invention involving a mono-static setup that uses amobile device, in accordance with an embodiment of the presentinvention. The exemplary operation 500 is between a tag 510 and a device520 hosting B-Tx/B-Rx. FIG. 6 is a block diagram showing an exemplaryoperation 600 of the present invention involving a mono-static setupthat uses a static device, in accordance with an embodiment of thepresent invention. The exemplary operation 600 is between a tag 610 anda device hosting B-Tx/B-Rx 620.

The devices hosting the B-Tx and B-Rx first communicate with each other(through an application) to coordinate a set of orthogonal channels(e.g. WIFI and/or Bluetooth channels) for transmission by B-Tx (CO andreception B-Rx (C_(r)), that will be employed in ambient, distributedbackscattering. The B-Tx then illuminates the orthogonal-band tags onchannel(s) C_(t); the tags respond back on either channels C_(t) andC_(r) (dual-band tags) or just C_(r) (frequency-shifting tags), which isthen picked up by B-Rx on channel C_(r). B-Rx then relays the tag'sresponse back to B-Tx, which records, and maintains an inventory of tagsread in the environment.

In a single phase backscattering protocol, the tag will perform a randomback-off (to alleviate collisions with other tags) before backscatteringits information. To be able to work with off-the-shelf WIFI andBluetooth devices in the environment as B-Tx and B-Rx, the tags willencode information at the granularity of WIFI/Bluetooth packets, and thepresence/absence of these packets will directly convey the tag'sresponse to B-Rx in a single phase. If two phase protocols need to beemployed between reader and tags, then B-Tx and B-Rx will coordinateclosely to perform a lock-step execution of the two phases—the B-Tx willilluminate all the tags, the response from the tags is then received andrelayed from B-Rx to B-Tx; B-Tx then polls a specific tag in phase 2,whose response at B-Rx is again relayed back to B-Tx.

Note that the B-Tx and B-Rx in our set-up could be a WIFI router and asmartphone, or a voice-activated device such as Amazon Echo® or GoogleHome® and a smartphone, or two smartphones, etc. The ability to leveragesuch existing devices adds diversity to the system without the need foradditional readers. For example, when a user carrying a smartphone walksabout the room, this increases the reliability of the tag reads byreading it from multiple different positions.

A description will now be given regarding dual-band tags for harmonicfrequency shift, in accordance with one or more embodiments of thepresent invention.

The dual band tag is designed to backscatter simultaneously on twowireless (e.g. WIFI/Bluetooth) channels. The present invention canaccomplish this with the help of harmonic tags that leverage theinherent non-linear characteristics of the chip in the tag to generatebackscattering at fundamental and harmonic frequencies simultaneously(typically first and second harmonics are the relatively stronger onesin terms of signal strength). The harmonic frequencies can be used asthe dual channel (C_(r)=f₃) for the B-Rx to receive the backscatteredsignal without having to suppress interference from B-Tx on thefundamental frequency (C_(t)=f₁). This is illustrated in FIG. 3. Atuning circuit can be added to the antenna to amplify the backscatteredsignal at the desired harmonic frequency.

A limitation of such harmonic tags is that f3 has to be an integermultiple of f₁, i.e., Δf=f₃−f₁=k·f₁, kϵ

¹⁺.

Hence, there is not much flexibility in the choice of the orthogonaltransmission and reception channels, which could affect the ability toleverage WIFI and Bluetooth channels on existing devices.

A description will now be given regarding frequency-shifting tags forarbitrary frequency shift, in accordance with an embodiment of thepresent invention.

To leverage existing smart devices and use their WIFI and Bluetoothchannels flexibly, we need to enable arbitrary frequency shifts with ourtags. To create such an arbitrary shift (Δf) of the reception channelfrom the transmission channel, while still keeping the tag completelypassive, the present invention moves the associated complexity to thetransmitter. In this case, B-Tx and B-Rx first coordinate the use ofthree channels for backscattering (instead of two in the case ofdual-band tags), two for transmission C_(t)={f₁, f₂} and one forreception C_(r)=f₃, such that f₂−f₁=f₃−f₂=Δf. When B-Tx transmits on twochannels f₁ and f₂ simultaneously, the frequency-shifting tag employs apassive mixer to generate frequencies of f₂+f₁ and f₂−f₁. The latter, Δfis then used to (frequency shift) backscatter the signal from f₂ tof₃=f₂+Δf. B-Rx, which is tuned to f3 then receives the backscatteredsignal. This is illustrated in FIG. 4.

For example, if Δf=25 MHz, then we can use two WIFI devices in 2.4 GHz,with two adjacent (orthogonal) channels being used at B-Tx (say channel1 and 6) and the third adjacent one at B-Rx (say channel 11) to readthese tags in consumer spaces. If one cannot deploy two WIFI channelssimultaneously (dual radio) at B-Tx, then one of these channels may besubstituted with a Bluetooth channel, which is available alongside WIFIin most smart devices today.

A noteworthy aspect of our orthogonal-band tag designs is that they arecompletely passive. They do not require the use of active componentslike additional oscillators and impedance-switching circuits toaccomplish the frequency shift. Tag antenna designs in accordance withthe present invention can be made to work with existing EPC Gen2 chips(two phase protocol) as well as other chips that enable a single phaseprotocol for use with off-the-shelf WIFI/Bluetooth devices.

The following is noted. While the B-Tx can employ WIFI and/or Bluetooth(called Ble hereafter) for both its TS and FS, the B-Rx can also employWIFI and/or Bluetooth/Ble. In one specific instantiation, we realize thefollowing set-up. The B-Rx is configured to receive a BS signal that isa Ble packet on a Ble advertisement channel (f₂). The B-Tx uses its WIFIinterface to embed the desired Ble packet at f₁. In other words, the Blepacket's contents are generated in such a way that when appropriatelyembedded into the WIFI packet (i.e. altering the contents of WIFIpacket), the resulting WIFI signal TS's frequency spectrum will have theBle signal at f₁ embedded in it. The B-Tx uses another WIFI interface toembed the two carrier tones, separated by Δf so as to generate the FSsignal. The contents of this WIFI packet are determined such that itsfrequency spectrum has two carrier tones separated by Δf. The two WIFIinterfaces are coordinated to generate the TS and FS signalssimultaneously. The tag then backscatters the Ble signal at f₁ to f₁±Δfto allow the B-Rx to receive the Ble packet at f₂.

A description will now be given regarding locating objects, inaccordance with one or more embodiments of the present invention.

While the previous sections discussed how to tag and monitor (read)various objects in indoor spaces, the present invention is also readilyequipped to localize the object that is being read. Recall that thepresent invention can leverage distributed backscattering, where apotentially mobile device like a smartphone can serve as the B-Tx orB-Rx. The mobility of the smartphone increases the diversity and hencereliability of reading the tags by allowing it to get in proximity ofthe tags. Hence, if the smartphone can be localized when it is reading atag, then the location of the tag can be approximately inferred from thelocation of the smartphone itself. The present invention leverages thisobservation of help locate the tags and hence keep track of where thevarious tagged products and objects are in the indoor space.

Localization of the smartphone can be accomplished in one of severalways.

(i) One could localize the phone acoustically with the help of the otherdevice involved in backscattering, namely a voice-activated smart device(e.g. Amazon Echo®, Google Home®, etc.). Both the B-Tx and B-Rx haveaccess to a microphone as well as a speaker, with the voice-activateddevice having a microphone array. One could leverage the array tolocalize the phone using conventional techniques like TDOA (TimeDifference Of Arrival).(ii) Another approach is to leverage multiple, static WIFI devices likesmart TVs, voice-activated wireless hubs, access points, etc. in theindoor space to multi-literate and localize the smartphone.

A description will now be given regarding other aspects of the presentinvention, in accordance with one or more embodiments of the presentinvention.

Recall that the present invention can be used for tagging objects inindoor spaces using existing wireless infrastructure and eliminating theneed for the deployment of any additional infrastructure such as RFID.While the B-Tx and B-Rx in the present invention are chosen to be twoseparate smart devices (e.g. Amazon Echo®, Google Home®, smartphones,etc.), they can also be co-located in the same smart device (illustratedin FIGS. 5 and 6). In the case of latter, they would use their existingradios to enable ambient, orthogonal-band backscattering but stillwouldn't require the need for RFID and its self-interferencecancelation.

If one is open to deploying a RF infrastructure in indoor spaces, eitherstandalone or being integrated into existing smart devices, then one candirectly leverage mono-static backscattering on the same device to tagindoor objects. Note that this requires a new wireless technology to beintegrated into existing devices or a new device to be deploy, both ofwhich add to cost. Further, being mono-static in nature (i.e., on asingle static device), its ability to reliably read all the tags in theenvironment could be significantly limited.

FIG. 7 is a flow diagram showing an exemplary method 700 for taggingobjects in indoor spaces using ambient, distributed backscatter, inaccordance with an embodiment of the present invention.

At block 705, encode a passive RF backscatter tag with informationregarding a product and associate the passive RF backscatter tag withthe product. Block 710 can be repeated for each product to be tagged.

At block 710, emit, by at least one RF backscatter transmitter, a RFsignal.

At block 715, reflect and frequency shift, by the passive RF backscattertag associated with the product, the RF signal.

At block 720, maintain, by a device hosting the RF backscattertransmitter, an inventory of tags.

At block 725, tag, by at least one RF backscatter receiver, the productby detecting a distributed ambient backscatter signal generated by areflection and a frequency shifting of the RF signal by the passive RFbackscatter tag. In an embodiment, the RF signal can be orthogonal tothe distributed ambient backscatter signal.

A description will now be given regarding consumer-deployed tags inconsumer spaces, in accordance with one or more embodiments of thepresent invention.

The ability to tag and monitor objects in indoor spaces is useful forthe consumer (user) to understand and subsequently optimize their usage.The user can procure the tags directly and attach them to objects thatare deemed important (e.g. passports, wallets, etc.) or those that theuser would like to track and monitor for usage and inventory (e.g. food,stationary and cleaning products). As the user walks around the space,the ambient, distributed backscattering technology, deployed through anapplication on the user's smart device (that accesses its' WIFI andBluetooth wireless interfaces) will read the tags in the vicinity andhence their associated products.

Given that the tags are static, as the user moves around, he can use thediversity of his positions and backscatter readings from the same tag tolocalize the tag with respect to the smart device. This will in turnlocate the objects that are tagged in the environment. To translate thetag/product location from relative (to smart device that is moving) toabsolute coordinates, one can leverage other static wireless devices inthe environment, such as a wireless access point and/or a voice-activatesmart speaker (e.g. Amazon Echo®, Google Home®, etc.). The staticwireless device(s) will localize the user's smart device, while thelatter localizes the tag, thereby allowing the user to locate the taggedproducts with respect to the location of the static wireless device(s).This would allow the user to create an inventory as well as a blue-printof where different products are located in the consumer space. Thelocalization of the user's smart device can be accomplished acousticallyif a static voice-activated smart device is leveraged. The latter,having access to a microphone array and speaker, can leverage the arrayto localize the user's smart device using conventional techniques likeTDOA (time difference of arrival). Another approach is to leverage WIFIfrom multiple, static devices (e.g., smart TVs, voice-activated wirelesshubs, access points, etc.) to multi-literate and localize thesmartphone.

Such a tracking and inventory feature provides several benefits to theconsumer. Some exemplary scenarios include: (i) the user can readilyaccess the inventory of products in his home, when he is shopping in astore; (ii) an application can remind the user at a configured frequencythat a particular product(s) is out of stock at home and needs to bere-stocked; (iii) the user can identify mis-placed objects around theindoor space (e.g., based on the backscatter signal and a map of properproduct locations).

FIG. 8 is a block diagram showing an exemplary store environment 800 towhich the present invention can be applied, in accordance with anembodiment of the present invention.

The environment 800 includes a multiple aisles 801-804, each having oneor more B-Tx's and one or more R-Tx's, e.g., one a per aisle or per areabasis, in order to tag objects on the shelves of the aisles.

Tags 810 can be read by B-Rx's 820 after being tagged by B-Tx's 810. Atleast some of the B-Tx's 820 and B-Rx's 830 are comprised in userdevices of users and/or employees walking through the aisles. The usersand/or employees can receive messages via their devices (e.g., phones)regarding information associated with items tagged by a user. In thisway, various aspects of the present invention, such as inventorycontrol, product misplacement, couponing, and so forth can be achieved.

FIGS. 9-10 are flow diagrams showing an exemplary method 900 formaintaining an in-store inventory, in accordance with an embodiment ofthe present invention.

At block 905, encode a set of passive RF backscatter tags such that eachof the tags is associated with a particular product for sale andincludes information regarding the particular product.

At block 910, transmit, by at least one RF backscatter transmitter, a RFsignal.

At block 915, reflect and frequency shift, by a set of passive RFbackscatter tags, the RF signal, each of the passive RF backscatter tagsassociated with a respective one of a plurality of sellable products ina given store area.

At block 920, tag, by at least one RF backscatter receiver, each of theplurality of sellable products by detecting a distributed ambientbackscatter signal generated by a reflection and a frequency shifting ofthe RF signal by the passive RF backscatter tags.

At block 925, maintain, by a device hosting the at least one RFbackscatter transmitter, an inventory of the plurality of sellableproducts in the given store area.

At block 930, incentivize, by the device hosting the at least one RFbackscatter transmitter, a user via a smart device of the user,responsive to the user deploying a tag relative to one of the pluralityof sellable products.

At block 935, identify, by the device hosting the at least one RFbackscatter transmitter, when an amount of a given one of the pluralityof sellable products is below a threshold level, responsive to thedistributed ambient backscatter signal.

At block 940, identify, by the device hosting the at least one RFbackscatter transmitter, a location misplacement condition of any of theplurality of sellable products responsive to the distributed ambientbackscatter signal and a mapping of correct product locations.

At block 945, provide, by the device hosting the at least one RFbackscatter transmitter, an out-of-stock indication at a user-selectablefrequency responsive to the distributed ambient backscatter signal.

At block 950, automatically re-order, by the device hosting the at leastone RF backscatter transmitter, regularly consumed ones of the pluralityof sellable products without user intervention.

At block 955, automatically mine, by the device hosting the at least oneRF backscatter transmitter, consumption profile and context informationof the plurality of sellable products to improve a performance of aproduct recommendation system.

A description will now be given regarding retailer-deployed tags inconsumer spaces, in accordance with an embodiment of the presentinvention.

The previous model provides complete freedom to consumers to determinewhich products they would like to tag and hence track/monitor. However,the information relating to the usage of such products and theshopping/consumption behavior of users, will not be available to theretailers. The availability of such information to the retailers willnot only help them provide value-added shopping services to consumersbased on analytics, but will also help them better design theirpersonalized advertisements and marketing strategy, product delivery andselling processes, as well as inventory management.

For the retailer to derive insights into the consumption of products inconsumer space, the retailer needs to influence the tagging of productseither directly or indirectly. Either the retailer can tag the productsdirectly at the warehouse or distribution center, or indirectlyincentivize (via coupons, discounts, rewards, etc.) the user (e.g., viaan application on a user device (e.g., a smart phone)) to tag productsonce they are in the consumer space. However, the application needed toenable and use ambient backscattering for reading the tags will beprovided by the retailer, thereby giving the retailer access to productinformation and their consumption in indoor spaces. The application canrun directly on the consumer's smart device, which serves as both theB-Tx and B-Rx. Alternatively, the retailer (such as Amazon®, Google® orApple®) can use their voice-activated smart devices (such as Echo, Home,etc.) as both the B-Tx and B-Rx; or use their static device as just theB-Tx, while the user's mobile device serves as the B-Rx; or use both thestatic and user devices as B-Tx, while user device serves as B-Rx. Inthe set-ups, where both static and user devices are involved, theapplication will run on both the B-Tx and B-Rx in a coordinated manner.In addition to reading of tags/products, the retailers can also trackthe location of the products, thereby providing contextual information,as in the previous use case.

Such product tracking and monitoring information can be integrated withthe retailers' e-commerce systems to enable several features: (i)automate re-ordering of regularly consumed products as appropriatewithout user intervention; (ii) incentivize and influence shoppingbehavior of users through personalized coupons; (iii) mine consumptionprofile and context information (e.g., location) of products to buildbetter recommender systems that can provide personalized suggestions forproducts in other related categories (based on context and wide-spreaddata from several customers); etc.

A description will now be given regarding retailer-deployed tags inretail spaces, in accordance with one or more embodiments of the presentinvention.

Similar to consumer spaces, the retailer can realize the ambientbackscatter technology directly in retail spaces/stores. The retailerwould deploy his static wireless devices as B-Tx and tag the products inthe store, while the users mobile devices will serve as the B-Rx.Instead of the users interacting with objects in their homes andconsumer spaces as in the previous use-case, they will now interactdirectly with products in retail stores. The retailer can use thistechnology to not only track inventory of products in the store inreal-time, but by allowing users to directly interact with the products,the retailer can get valuable insights into user shopping behavior thatcan used to influence their shopping decisions in real-time.

Such a feature delivers several benefits to the retailer: (i) enablesreal-time inventory of products in the store; (ii) capture real-timeinteraction of customers with products to influence buying decisionsthrough targeted coupons, recommendations, etc.; (iii) better shoppingexperience for users by providing real-time assistance on interestedproducts directly on their phones; etc.

A description will now be given regarding venue-deployed tags incommercial spaces, in accordance with one or more embodiments of thepresent invention.

Another interesting use case of this technology is their application inlarge venues, both indoor and outdoor, where they can be deployed toprovide navigation assistance as well as location-based targetedinformation. The venue owner will deploy the B-Tx and the tags, whilethe users will bring their own smart devices that will serve as B-Rx andinteract with the tags directly. Given the inexpensive nature of thesetags, they can be deployed densely to serve as landmark beacons that canenable several applications: (i) navigation in large venues like themeparks, convention/event centers, hospitality centers, indoor or outdoortourist attractions, etc.; and (ii) deliver location-specificinformation that could be useful to visitors in applications such asexhibit description in museums/zoos, landmark description in populartourist spots, event information in different parts of an event center,etc.

FIG. 11 is a block diagram showing an exemplary environment 1100 enabledwith tagged navigation markers to which the present invention can beapplied, in accordance with an embodiment of the present invention.

The navigation markers 1190 are fixed objects that can be used fornavigation purposes. Passive RF backscatter tags 1110 are affixed toeach of the navigation markers 1190 which can be tagged in order toreceive information responsive to tagging.

At least one B-RX 1130 and at least one B-Tx 1120 are included inenvironment 1100, can be associated with the navigation makers and/orare associated with user devices (e.g., smart phones) of users. Thenavigation marker 1190 could have a speaker or display 1191 coupled toit that announces or shows navigation information to a user.

The benefits to venue owners (private or government) include (i) betteruser experience in navigating and exploring the venue; (ii) moreefficient use of venue resources by better-informed customers; (iii)traffic analytics for venue owner to better restructure venue facilitiesand provision resources; and so forth.

FIGS. 12-13 are flow diagrams showing an exemplary method 1200 forindoor navigation assistance, in accordance with an embodiment of thepresent invention.

At block 1205, encode a set of passive RF backscatter tags such thateach of the tags is associated with a particular product for sale andincludes information regarding the particular product.

At block 1210, transmit, by at least one RF backscatter transmitter,hosted on a device, a RF signal.

At block 1215, reflect and frequency shift, by a set of passive RFbackscatter tags, the RF signal, each of the passive RF backscatter tagsassociated with a respective one of a plurality of navigation markers ina given venue.

At block 1220, tag, by at least one RF backscatter receiver, each of theplurality of position markers by detecting a distributed ambientbackscatter signal generated by a reflection and frequency shifting ofthe RF signal by the passive RF backscatter tags.

At block 1225, maintain, by the device hosting the at least one RFbackscatter transmitter, an inventory of locations of the plurality ofnavigation markers in the given venue.

At block 1230, store and provide to a user, by the device hosting the atleast one RF backscatter transmitter, navigation information. In anembodiment, the navigation information is provided relative touser-observable ones of the navigation markers.

At block 1235, store and provide to a user, by the device hosting the atleast one RF backscatter transmitter, a set of one or more nextlocations likely to be of interest to a user, based on predicted usertrajectories.

At block 1240, store and provide to a user, by the device hosting the atleast one RF backscatter transmitter, descriptive information about anobject proximate to a user.

The information stored and provided to the user in the preceding blockscan be provided to the user in acoustic form or visual form.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as SMALLTALK, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Reference in the specification to “one embodiment” or “an embodiment” ofthe present invention, as well as other variations thereof, means that aparticular feature, structure, characteristic, and so forth described inconnection with the embodiment is included in at least one embodiment ofthe present invention. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment”, as well any other variations,appearing in various places throughout the specification are notnecessarily all referring to the same embodiment.

It is to be appreciated that the use of any of the following “/”,“and/or”, and “at least one of”, for example, in the cases of “A/B”, “Aand/or B” and “at least one of A and B”, is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of both options (A andB). As a further example, in the cases of “A, B, and/or C” and “at leastone of A, B, and C”, such phrasing is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of the third listedoption (C) only, or the selection of the first and the second listedoptions (A and B) only, or the selection of the first and third listedoptions (A and C) only, or the selection of the second and third listedoptions (B and C) only, or the selection of all three options (A and Band C). This may be extended, as readily apparent by one of ordinaryskill in this and related arts, for as many items listed.

The foregoing is to be understood as being in every respect illustrativeand exemplary, but not restrictive, and the scope of the inventiondisclosed herein is not to be determined from the Detailed Description,but rather from the claims as interpreted according to the full breadthpermitted by the patent laws. It is to be understood that theembodiments shown and described herein are only illustrative of thepresent invention and that those skilled in the art may implementvarious modifications without departing from the scope and spirit of theinvention. Those skilled in the art could implement various otherfeature combinations without departing from the scope and spirit of theinvention. Having thus described aspects of the invention, with thedetails and particularity required by the patent laws, what is claimedand desired protected by Letters Patent is set forth in the appendedclaims.

What is claimed is:
 1. A product tagging system, comprising: at leastone RF backscatter transmitter configured to emit a Radio Frequency (RF)signal on a frequency; a passive RF backscatter tag associated with aproduct and configured to reflect and frequency shift the RF signal to adifferent frequency; and at least one RF backscatter receiver configuredto read the product on the different frequency by detecting adistributed ambient backscatter signal generated by a reflection andfrequency shifting of the RF signal by the passive RF backscatter tag.2. The product tagging system of claim 1, wherein the backscatter tag isconfigured to frequency shift and backscatter the RF signal from the atleast one RF backscatter transmitter onto a different orthogonal channelfor reception by the receiver.
 3. The product tagging system of claim 1,wherein the at least one RF backscatter transmitter and the at least oneRF backscatter receiver coordinate usage of three channels forbackscattering, with two of the three channels configured fortransmission and a remaining one of the three channels configured forreception, and wherein the passive RF backscatter tag comprises apassive mixer to generate a mixed frequency detected as the distributedambient backscatter signal on the one of the three channels.
 4. Theproduct tagging system of claim 3, wherein a transmission from the atleast one RF backscatter transmitter comprises a signal required forshifting the frequency of the distributed ambient backscatter signal bythe passive tag.
 5. The product tagging system of claim 1, wherein thepassive backscatter tag is configured to backscatter the RF signalsimultaneously on a first band used by the at least one RF backscattertransmitter and a second band that is orthogonal to the first band andused by the at least one RF backscatter receiver.
 6. The product taggingsystem of claim 1, wherein the passive RF backscatter tag generates thedistributed ambient backscatter signal as multiple signals comprising afundamental frequency and at least one harmonic frequency.
 7. Theproduct tagging system of claim 6, further comprising a tuning circuit,coupled to an antenna, configured to amplify the at least one harmonicfrequency.
 8. The product tagging system of claim 1, wherein one of theat least one RF backscatter transmitter and the at least one RFbackscatter receiver are hosted in a same mobile or stationary device ina mono-static configuration.
 9. The product tagging system of claim 1,wherein one of the at least one RF backscatter transmitter and the atleast one RF backscatter receiver are hosted on two separate devices ina bi-static configuration.
 10. The product tagging system of claim 1,wherein the passive RF backscatter tag stores information, and modulatesthe RF signal to convey the information to the at least one RFbackscatter receiver.
 11. The product tagging system of claim 1, whereinthe passive RF backscatter tag encodes the information at a packet-levelor bit-level granularity, and a response of the tag is directly conveyedto the at least one RF backscatter receiver in the form of an absence ora presence of a packet or modulation of bits in a single phaseencompassing both a transmission and a reflection of the backscattersignal.
 12. The product tagging system of claim 1, wherein the at leastone RF backscatter transmitter and the at least one RF backscatterreceiver are embodied in existing re-purposed devices having a primarypurpose other than tagging products.
 13. The product tagging system ofclaim 1, wherein a device hosting the at least one RF backscattertransmitter or at least on RF backscatter receiver is configured tomaintain an inventory of tags read in a given environment.
 14. Theproduct tagging system of claim 1, wherein the at least one RFbackscatter transmitter is configured to infer a location of the productbased on the location of the at least one RF backscatter receiver, wherethe distributed ambient backscatter signal from the tag was received.15. The product tagging system of claim 14, wherein the location of thebackscatter receiver is inferred using RF and acoustic devices availablein the environment.
 16. The product tagging system of claim 1, whereinthe at least one RF backscatter receiver comprises a plurality of RFbackscatter receivers for acquiring backscatter signal readings frommultiple different locations.
 17. The product tagging system of claim 1,wherein the plurality of channels used for backscatter transmission andreception is embodied in standardized RF channels available in commoditydevices.
 18. The product tagging system of claim 1, further comprising afirst and a second transmission channel, wherein the first transmissionchannel carries the desired RF carrier signal, and the secondtransmission channel carries the two carrier tones needed to generatethe distributed ambient backscatter signal.
 19. The product taggingsystem of claim 18, wherein the desired RF carrier transmission signalis embedded within a carrier of another standardized RF technology tofacilitate reception by the at least one RF backscatter receiver.
 20. Amethod for product tagging, comprising: emitting, by at least one RFbackscatter transmitter, a Radio Frequency (RF) signal on a frequency;reflecting and frequency shifting, by a passive RF backscatter tagassociated with a product, the RF signal to a different frequency; andreading, by at least one RF backscatter receiver, the product on thedifferent frequency by detecting a distributed ambient backscattersignal generated by a reflection and frequency shifting of the RF signalby the passive RF backscatter tag.